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Influence of brown trout, Salmo trutta L., predation on the benthic fauna of earthen ponds
Author(s) -
WAHAB M. A.,
STIRLING H. P.,
ROBERTSON D. A.
Publication year - 1989
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.1989.tb00339.x
Subject(s) - biology , chironomidae , brown trout , salmo , benthic zone , predation , oligochaeta (plant) , fauna , biomass (ecology) , benthos , fishery , population , ecology , trout , fish <actinopterygii> , larva , demography , sociology
. Sections of the bottom of three earthen fish ponds in central Scotland were enclosed to prevent access by juvenile brown trout, Salmo trutta L., stocked at different densities from July to October. Monthly benthic samples were taken inside and outside the enclosures with a suction sampler. The benthos was dominated by Oligochaeta, whose density and biomass were significantly lower outside the enclosures; production was also lower outside but the P:B ratio was much higher. Total Chironomidae were more abundant outside, but not the larger predatory species which appeared to control the inside population. Species diversity of Oligochaeta and Chironomidae was greater outside while mean size was reduced, presumably as a result of size‐selective predation by trout. Numbers of Mollusca and Asellidae were lower in the presence of fish, but Hirudinea and Sialidae were unaffected. Increasing fish density boosted chironomid numbers and biomass, indicating a predominant response to organic enrichment, but reduced the numbers of most other benthic groups presumably as a result of predation.